Question

what happens when you change frequency

Answer 1

\[f = \frac{ v }{ \lambda } \] frequency is equal to the speed at which the wave travels divided the wavelength, as is generally the velocity in a medium is taken as constant, a change in frequency only imply a change in the wavelength then if increases the frequency decreases wavelength.

Answer 2

On radio, you start listening to a differernt station, on TV you watch different channel etc.